Line up your iconic and often unkillable serial killers. March in your undead armies by their hundreds. But frankly, if you want to creep out even the most demanding horror fans, all you need to do is show them a clown chilling in a storm drain. 

Pennywise the Dancing Clown in “It” is truly a thing of nightmare fuel, so much so that even his creator, Stephen King, believes Pennywise will outlive him as terror that will never die. But there’s so much more to King’s iconic monster, which has a strict diet of fear and children. For one, he’s an ageless being that doesn’t age between the Losers Club’s first encounter and their pulse-pounding reunion and 27 years later, when they’re still scarred from the otherworldly trauma. Their dread of what’s waiting down in the belly of their hometown keeps It ticking over and leads to It taking many shapes and sizes throughout the story that spans almost three decades.

Besides the nightmarish clown with a button red nose, Pennywise also appears to the Losers as a wolfman, a diseased homeless man living under a house, a lonely old lady, and giant ax-swinging lumberjack Paul Bunyan. However, the truth behind Derry’s best-kept and bleakest secret is that while Pennywise may creep out kids in the form of a clown, his true nature is even weirder.

When we first meet Pennywise in King’s classic horror, he claims he got blown away from a circus and found himself washed down a storm drain, where he meets doomed little Georgie Denborough. It’s all a front, though; Pennywise might look like a clown, but it doesn’t take long for the mask to slip and the monster to reveal Itself. The clown is the shape that Pennywise is most commonly seen in when he’s stalking the streets of Derry and getting into the heads of Bill and the Losers, and it was a villain Stephen King chose carefully.

Pennywise came about from a passion to write a book that, as King put it to an audience in Hamburg in 2013 (via YouTube), had “all the monsters in it.” Throwing vampires, werewolves, and mummies (oh my!) into the mix, it was clear that the author needed something special to keep them all together. “There ought to be one binding, horrible, nasty, gross creature. The kind of thing that you don’t want to see. It makes you scream just to see it.'” From there, King had his light bulb moment. “So I thought to myself, ‘What scares children more than anything else in the world?’ And the answer was ‘clown.'” 

He’s not wrong. Besides the Bill Skarsgård and Tim Curry’s iterations, there are enough scary clowns in horror that we made our own list. But thanks to some extra special tricks, Pennywise sets himself apart from the rest of the circus.

One of Pennywise’s many powers is the ability to shapeshift into anything his victim is afraid of. The clown isn’t always present, but for the most part is the creature’s go-to disguise. As King has said numerous times in interviews, clowns are always scary and that’s why they became the main form of the monster in “It.” Speaking to Yahoo, the author recalled his aversion to the big-shoe-wearing entertainers. “I mean, if I were a sick kid and I saw a f***ing clown coming, all the red lines would go off on my gear, because I’d be scared to death! So kids are scared of clowns.”

In both the book and the film, individual members of the Losers Club are all toyed with by Pennywise/IT in different forms. For Ben Hanscom, It’s a mummy. For Bill Denborough, It’s his dead brother. For germophobe Eddie Kaspbrak, It was a homeless man offering sexual favors (yep, that’s in the book). Nevertheless, Pennywise the Clown would always appear with every encounter, until our heroes learned the beast’s true history. Down in the sewers of Derry, the Losers are presented with something that both the readers and even some of the stars that brought “It” to life had some trouble with.

By the end of “It,” The Losers have learned that Pennywise is an ancient evil that’s not even of this world. An alien that landed on Earth in the 16th century from a dimension known as the Macroverse, Its method of hunting was put into effect long before our heroes faced It. They eventually track It to Its hidden domain deep beneath Derry, where It presented Itself as close to Its proper form as It could. It was a terrible one.

In the book’s final act, Pennywise takes the guise of a giant spider laying eggs, and appears as such in both the 1990 miniseries and the more recent big-screen adaptation from director Andrés Muschietti. The first attempt at live-action was a mix of stop-motion and puppetry and was an absolute killjoy all round, but it was true to the book. Nevertheless, it didn’t sit well with the original Pennywise, Tim Curry, who later said he “was very disappointed by the ending, when I turned into a rather unconvincing spider.”

Of course, just like the nature of “It” itself, fear is in the eye of the beholder, as Curry rightfully pointed out: “I think whatever scares the pants off you when you’re a child is an image that always stays with you.” Well, sure. Well, it’s better than a spotlight, right?

After the clown, the lumberjack and the sewer-dwelling spider, the true form of Pennywise is known as the Deadlights. Described as orange lights, any human that is unfortunate to look upon these glowing rays runs the risk of going insane. Used as to ensnare victims by finally revealing Its true form, the Deadlights in the book briefly got hold of Bill during his childhood, though fortunately he escaped. In the 2017 adaptation and its sequel, Beverly and Richie endured the same experience, but were also cut free from the gaze. No matter what version you’re watching, though, there’s no denying that it certainly makes for one of the weaker endings in King’s back catalog. 

Years later the Deadlights would return in King’s “Dark Tower” series when the Crimson King (who is thought to be Pennywise) uses the Deadlights to move between levels of the Dark Tower. He even mentions Derry at one point. This intertwining of worlds still doesn’t make these hellish fairy lights cool, though. Regardless of being floating yellow balls that drive folks insane, they really don’t hold a candle to the creature’s most commonly used form. Pennywise will always leave Losers and horror fans alike dreading a clown that’s smiling just a bit too much.